Surface hierarchical porosity in poly (ɛ-caprolactone) membranes with potential applications in tissue engineering prepared by foaming in supercritical carbon dioxide

- Poly (ɛ-caprolactone) membranes with surface porosity were prepared using supercritical CO2 foaming.
- The membranes displayed surface hierarchical macroporosity and pore interconnectivity between both sides of the membrane.
- The surface hierarchical porosity consists of two pores types, type 1 with an average pore size of 300-500 μm and type 2 of 15-50 μm.
- Hierarchical porosity was achieved by using pressures of >100 bars and <300 bars, temperatures lower than 45 °C and depressurization over several steps.
- Membranes showed good biocompatibility in cell culture assays.